SHJ,
Thanks for your detailed response. A very sad and unwelcome story.
I've been a Mac user since the days of System 6 (1988) and I use only Apple hardware for my personal computing needs - a MacBook Pro, two iPhones, an iPad and an Apple Watch. I use both Linux and Windows (reluctantly) for work but that's a different story.
One observation I will make related to your experiences is that I have found that Time Machine doesn't live up to its hype. It is promoted by Apple as a painless panacea, but I've found it very unreliable and buggy, and I gave up trying to use it several years ago. I now use non-Apple backup software as I related in my previous post.